IB/mthca: Use uninitialized_var() for f0
Commit 9db48926 ("drivers/infiniband/hw/mthca/mthca_qp: kill uninit'd
var warning") added "= 0" to the declarations of f0 to shut up gcc
warnings. However, there's no point in making the code bigger by
initializing f0 to a random value just to get rid of a warning;
setting f0 to 0 is no safer than just using uninitialized_var(), which
documents the situation better and gives smaller code too. For example,
on x86_64:
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-16 (-16)
function old new delta
mthca_tavor_post_send 1352 1344 -8
mthca_arbel_post_send 1489 1481 -8
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c
index 11f1d99..0e9ef24 100644
--- a/drivers/infiniband/hw/mthca/mthca_qp.c
+++ b/drivers/infiniband/hw/mthca/mthca_qp.c
@@ -1591,7 +1591,13 @@
int i;
int size;
int size0 = 0;
- u32 f0 = 0;
+ /*
+ * f0 is only used if nreq != 0, and f0 will be initialized
+ * the first time through the main loop, since size0 == 0 the
+ * first time through. So nreq cannot become non-zero without
+ * initializing f0, and f0 is in fact never used uninitialized.
+ */
+ u32 uninitialized_var(f0);
int ind;
u8 op0 = 0;
@@ -1946,7 +1952,13 @@
int i;
int size;
int size0 = 0;
- u32 f0 = 0;
+ /*
+ * f0 is only used if nreq != 0, and f0 will be initialized
+ * the first time through the main loop, since size0 == 0 the
+ * first time through. So nreq cannot become non-zero without
+ * initializing f0, and f0 is in fact never used uninitialized.
+ */
+ u32 uninitialized_var(f0);
int ind;
u8 op0 = 0;